A technology for producing induced pluripotent stem cells is a technology of making cells similar to embryonic stem cells using animal somatic cells, and comprises culturing cells under specific culture conditions in the presence of four known reprogramming factors (Oct4, Klf4, Sox2, and cMyc). Induced pluripotent stem cells made by this method have advantages in that they can differentiate into all tissue-specific cells and can be used for cell therapy agents that pose no ethical problems, but these induced pluripotent stem cells have disadvantages in that they are produced with low efficiency, are difficult to guarantee their safety and are not completely similar to embryonic stem cells.
Since 2006 in which induced pluripotent stem cell technology was developed, many studies on this technology have been conducted and a variety of compositions resulting from these studies have been used to increase the efficiency with which induced pluripotent stem cells are produced. As a result, 23 papers have reported that the efficiency of production of induced pluripotent stem cells was successfully increased using specific composition, and 6 papers have reported that induced pluripotent stem cells were successfully produced even in the absence of one or more reprogramming factors.
Up to date, studies have been conducted mainly to increase the efficiency with which induced pluripotent stem cells are produced. However, when only the efficiency of production of induced pluripotent stem cells is increased in a state in which the verification of safety of induced pluripotent stem cells is insufficient, it does not appear that induced pluripotent stem cells are clinically applicable. Thus, in order to increase the clinical applicability of induced pluripotent stem cells, studies focused on increasing the safety of induced pluripotent stem cells are necessarily required, and a method of making induced pluripotent stem cells more similar to embryonic stem cells should be developed.
In prior art technologies related to the present invention, Korean Patent Registration No. 10-1211610 (Dec. 6, 2012) discloses a composition for inducing dedifferentiation from somatic cells to embryonic stem cell-like cells by use of Bmi1, a MEK inhibitor and a GSK inhibitor, and a method for producing embryonic stem cell-like cells using the composition. Korean Patent Registration No. 10-1211624 (Dec. 6, 2012) discloses a composition for inducing dedifferentiation from somatic cells to embryonic stem cell-like cells by use of Shh, a FGFR tyrosine kinase inhibitor, a MEK inhibitor and a GSK inhibitor, and a method for producing embryonic stem cell-like cells using the composition. In addition, Korean Patent Laid-Open Publication No. 10-2010-0101764 (Sep. 20, 2010), Korean Patent Laid-Open Publication No. 10-2011-0094348 (Aug. 23, 2011), Korean Patent Laid-Open Publication No. 10-2012-0094488 (Aug. 24, 2012), and Korean Patent Laid-Open Publication No. 10-2012-0121084 (Nov. 5, 2012) disclose a useful culture method and medium for producing and maintaining pluripotent stem cells, etc.
Several papers related to the background of the present invention have reported that treatment with compositions increases the efficiency with which induced pluripotent stem cells are produced, but whether this treatment with compositions can inhibit the mutation of induced pluripotent stem cells is not known. In particular, it has not been reported that the use of a composition containing a MEK inhibitor, an ALK5 inhibitor, a ROCK inhibitor or an antioxidant can inhibit mutation or DNA damage that is a problem occurring in the production of induced pluripotent stem cells, and thus can provide stable induced pluripotent stem cells.
Accordingly, the present inventors have found that a composition containing the ROCK inhibitor thiazovivin, the MEK inhibitor PD0325901, the ALK5 inhibitor SB431542 or the antioxidant L-ascorbic acid maintains chromosomal stability by inhibiting structural and numerical mutations or DNA damage in induced pluripotent stem cells, thereby completing the present invention.